Where the heck was Fluffy in every single book after The Sorcerer's Stone?!

My math teacher from freshman year is a HUGE Harry Potter fan, and especially he loves Hagrid and all Hagrid's critters. So he said he wish Hagrid had showed up at the Battle of Hogwarts riding on Fluffy. Unstoppable.

He asked me to draw it for him, so I decided to do a digital painting. This is out of my comfort zone a bit, but I really like how it came out. I decided to try using a textured brush for nearly the whole painting, and I like the result.